William Hogg Watt (1818–1893) was a 19th-century Member of Parliament in the Manawatu region of New Zealand.
He represented the Rangitikei electorate from 1866 to 1868 when he resigned, and then the Wanganui electorate from 1881 to 1884 when he was defeated.
He was Mayor of Wanganui in 1881, succeeded by Gilbert Carson.